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Innovations in Verification of Hearing Aid Fitting in Children
Monika BaumannHörakustik-Meisterin, Pädakustikerin
ANSI-standard for RECD, use of MAOF and SII normative range
compared in common measurement systems
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Requirements in Verification
• Standardization of the RECD measurement
– ANSI S3.46-2013 / RECD
• SII Normative Values for children
– PaedAmp, University of Western Ontario
• MAOF-range as target for frequency lowering
– Maximum Audible Output Frequency Range
– PaedAmp, University of Western OntarioImplication on / Application in
common Verification Equipment
MAOF
SII Normative
Values
ANSI S3.46-2013
RECD
www.dslio.com
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RECD
Innovation, accuracy, application and implementation
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RECD “classic”
Real-ear response
250 500 1k 2k 4k 8k
dB 908070605040302010
0-10-20-30
Coupler response
Measured RECD
dB SPL(real ear) – dB SPL(HA2 coupler) = RECD
Basic measurement principle since 1995 by use of the HA2 coupler:
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ANSI Standard S3.46-2013 / RECD
• ANSI S3.46: North American Standard for REM– 2013: RECD included in S3.46 recommends to
• use of HA1 coupler
• use of a high-impedance transducer for signal application
• use of ear mold / foam tip for both – coupler and on ear measurement
– Why?
– Consequences?
– Changes in Application?
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RECD – Accuracy of methodType of coupler
HA1-RECDwith ITE-coupler
HA2-RECDwith BTE-coupler
Bagatto et al. 2005: Clinical Protocols for Hearing Instrument Fitting
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RECD – Accuracy of methodTransducer and earmold tubing length
Earmold tubing length: 45 mm
Earmold tubing length: 35 mm
Bagatto et al. 2005: Clinical Protocols for Hearing Instrument Fitting
The shorter the earmold tubing length:➢ The fewer resonances➢ the lower the impact of different RECD
transducers
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RECD – Accuracy of methodRECD with foam tip vs. individual earmold
• Earmold tubing length
– Short and standard for ear tips
– Longer and individual in earmolds
• Used for
– Audiometry with inserts: ear tips
– HA fitting: earmold
• Consequence for RECD:
– High precision requires two RECDs!
Von Biha - Bundesinnung der Hörgeräteakustiker KdöR - biha - Bundesinnung der Hörgeräteakustiker KdöR, CC BY-SA 3.0,
https://commons.wikimedia.org/w/index.php?curid=47520907
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RECD – Accuracy of methodFoam tip to earmold difference
• Age-related RECD averages exist for foam tip and for earmold
• the hearing loss may have been measured with foam tip, while the HA is couple with earmold
– Measure RECD twice?
– Develop correction values!
• Corrective Values developed and implemented in Verifit VF2
New RECDs and New ANSI Standards: Revisiting RECD Basics and Applications, Susan Scollie, 2015 (www.audiology-online.com )
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Variances of couplers – used for RECD
HA1(2)-RECDrecalculated
Verifit1, RM500SL, Axiom
HA1-RECDcoupler measured
Aurical, Verifit Affinity 2.0
HA1-RECDwith RECD SPL-probe
✔✔ ✔
New software
New software
✔WRECD
Verifit2 VF-2 with 0,4 cm3-Kuppler
recalculated to HA1-RECD
HA2-RECDHA2-RECD
Child 0-24 months
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WRECD with Verifit VF2 (Video)
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RECD SPL-Probe in Affinityinfluence of insertion depth for RECD SPL probe vs. tube length in HA2-RECD
Source: Interacoustics
Age-related RECD with earmold measured with HA2-couplerAge-related RECD measured with RECD-tip
Comparable with HA1-RECD
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RECD with SPL probe (Video)Example from Affinity 2.0
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HA2-RECD with earmold (Video)Example from Aurical
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SII
Normative Values for Paediatric Fitting Verification
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Fitting Evaluation: SII normative valuesonly for pediatric fitting! (DSL child)
https://www.uwo.ca/nca/research/research_areas/cal/Publications.html
Source: Marlene P. Bagatto, 2012: “Development and Evaluation of an Audiological Outcome Measure Guideline for Use with Infants, Toddlers and Preschool Children”
www.dslio.comPedAMP “Aided SII Normative Values Form PDF”
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PTA & SII
𝑃𝑇𝐴 =
𝐻𝑇𝐿500 𝐻𝑧 + 𝐻𝑇𝐿1000 𝐻𝑧 + 𝐻𝑇𝐿2000 𝐻𝑧3
Calculation of PTA Calculation SII
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Normative Values for SIIExample from Audioscan Verifit VF2: calculation evaluated
PTA: 48 dB HL
SII65dB 74%
SII55dB 65%
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VERIFICATION
Comparison of Equipment used for Verification
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Common REM Equipment in Pediatrics
• Software Versions of REM equipment used:
– Affinity2.0 Affinity Suite Software Vers. 2.11.0
– Aurical HIT & FreeFit Otosuite Software Vers. 4.84.00
– Verifit & Verifit2 Verifit2 Software Vers.4.16.5
• Essential:
– Simulated REM measurements in test box with infants and young children
– RECD: Real-Ear-to-Coupler measurement Gold standard: measured
– ISTS International Speech Test Signal
– Percentile analysis used to display measurement results: LTASS, 99th
percentile and 30th percentile used to display dynamics of speech
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Formally, all measure in the same way!Question: Does that also mean that the display shows exactly the same measurement results?
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Introduction to the graphical display of REM simulated, coupler based Verification
of Hearing Aids in:
Verifit2, Aurical PMM, Affinity2.0,
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Verifit2 / Verifit: Display coupler based REAR*** UCL calculated (Pascoe) in dB SPL + (W)RECD = dB SPLReal Ear simulated
+ + + BOLT target for MPO DSLv5
MPO measured in dB SPLHA4-coupler + (W)RECD
Implementation of (W)RECD (average or measured):- Hearing threshold and UCL in dB SPLReal Ear simulated
- dBSPLHA4-coupler + (W)RECD = dB SPLReal Ear simulated- DSLm5 Zielkurve Original- MLE applied to the speaker signal
Hearing threshold right/left in dB HL + RETSPLtransducer + (W)RECD = dB SPLReal Ear simulated
HA measured with ISTS 65 dB in dB SPLHA4-coupler + (W)RECD = dB SPLReal Ear simulated
LTASSDynamikbereich von ISTS
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Aurical PMM: Display coupler based REAR
UCL estimated (Pascoe) in dB SPL + RECD = dB SPLReal Ear simul.
BOLT target for MPO DSLv5 Original
MPO measured in dB SPLHA2 coupler + RECD
Residual Dynamic Range
DSL-Zielkurve für 65 dB SpracheDSLv5 Original
HA measured with ISTS 65 dB in dB SPLHA2-coupler + RECD = dB SPLReal Ear simulated
---- LTASS Dynamics of ISTS
Implementation of RECD (average or measured):- Hearing threshold and UCL in dB SPLReal Ear simulated
- dBSPLHA2-coupler+ RECD = dBSPLReal Ear simulated- DSLm5 targets Original- MLE ??
Hearing threshold in dB HL + RETSPLtransducer
+RECD = dB SPLReal Ear simulated
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Affinity2.0: Display coupler based REAR
MPO measured in dB SPLHA2-coupler + RECD
BOLT target for MPO DSLv5
DSL-target for 65 dB speechDSLv5 Original
HA measured with ISTS 65 dB in SPLHA2-coupler
+ RECD = dB SPLReal Ear simulated
LTASS Dynamic of ISTS
UCL estimated (Pascoe) in dB SPL + RECD = dB SPLReal Ear Simulated
Hearing threshold in dB HL + RETSPLtransducer +RECD = dB SPLReal Ear simulated
Residual Dynamic Range
Implementation of RECD (average or measured):- hearing threshold and UCL in dBSPL
- dBSPLHA2-coupler+ RECD = dBSPLReal-Ear simulated- DSLm5 target Original- MLE ??
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Case study for comparison of results
Affinity2.0, Aurical, Verifit2
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Case Study: Comparison of REM equipment
• Child 6 years old:– Audiometry with headphones
– RECD age-related averages
– BTE hearing aids
– Closed earmold
– DSLv5 child
– HA fitted and fine tuned with Verifit (precondition for comparison)
Calculation of PTA:PTA = (HV500Hz + HV1000Hz + HV2000Hz )/3PTA = (40 dB + 45 dB + 60 dB)/3 = 48 dB
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First-Fit and Fine tuning with Verifit2 VF-2
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First Fit and Fine tuning with Verifit2 VF-2
SII-Werte:ISTS 65 dB: 74%ISTS 55 dB: 62%PTA: 48 dB
PTA: 48 dB HL
SII55dB 62%
SII65dB 74%
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HA fitted with VF2 measured in Aurical
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HA fitted with VF2 measured in Aurical
Verifit2 fit measured with AuricalOtosuite Software Version 4.84.0.61
Verifit2 fitVerifit2 Software Version 4.12.4
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Fit & fine tuning to target in Aurical
PTA = 48 dB HL
SII55dB 56%
SII65dB 73%
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HA fitted with VF2 measured with Affinity
Verifit2 fitVerifit2 Software Version 4.16.5
Verifit2 fit measured with AffinityAffinity Suite Software Version 2.11.00
At 2-4 kHz around 7-10 dB are missing
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Fit and fine tuning with Affinity: SII
PTA = 48 dB HL
SII55dB 73%
SII65dB 73%
?
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Comparison of SII values after Fine tuning
Verifit2 /
Verifit 1
Aurical /
Calisto
Affinity /
Equinox
PTA = 48 dB HL
SII65dB 73%/74%
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Comparison of SII values after Fine tuning
Verifit2 /
Verifit 1
Aurical /
Calisto
Affinity /
Equinox
PTA = 48 dB HL
SII65dB 73%/74%
SII55dB 73%
SII55dB 62%
SII55dB 56%
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MAOF
Maximum Audible Output Frequency Range
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Verification of Frequency Lowering
• Guideline for Pediatric Fitting
– UWO, Kanda 2014
• Use of Frequency Lowering & Verification
– Check & verify audibility for fricatives
– Guidance
• Signals: UWO /s/ & /sh/
• Addendum 2, page 44-62
Quelle: www.dslio.comUniversity of Western Ontario, Susan Scollie et al.: Ontario
Infant Hearing Program OIHP
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Signals for Verification: /s/ & /sh/
• Frequency specific speech signals
• Extracted from ISTS
• Filtered and adapted
– for better differentiation
– adapted to level in speech
• /s-10dB/ and /sh-6dB/ when selecting 65 dB speech level
Spectrum of the ISTS at 65 dB and
LTASS from UWO /s/ and /sh/
Abb. Quelle: Ontario Infant Hearing Program (2014.1),
www.dslio.com
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UWO_s Ling_s
UWO_sh Ling_sh
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Determination of MAOF range in measurement results from ISTS 65 dB without Frequency Lowering
• Fitting & fine tuning to DSLm5[child]
– Without FL activated
• Determination of MAOF range:
– Dynamic range of ISTS 65 dB
• intersection between LTASS and HTL
• intersection between 99th percentile and HTL
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MAOF in Verifit2: check audibility of /s/ without Frequency Lowering activated
• Preconditions:
– ISTS 65 dB result optimized
– Select /s/ for next test
• Display MAOF-range in VF2
– Select /s/
– Select view “MAOF”
– Record measurement
Result:/s/ is below MAOF-range and may in normal speech not be audible
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MAOF in Verifit2: Fit Frequency Lowering
• Fit & Finetune– Activate frequency lowering
– Select /s/ for further test
– Move the output for /s/ into MAOF range by help of frequency lowering
– Back shoulder of /s/ should be placed in the MAOF range
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MAOF in Verifit2: optimize Frequency Lowering
• Optimize FL:
– Measure /sh/
– /sh/ and /s/ must show clear deviation
– If necessary reduce /s/ in clarity to ensure differentiation
– Find a balance between utmost audibility and speech distortion
• Efficacy needs to be validated
– Phoneme Perception Test
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Verification with MAOF (Video)
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Conclusions
• Measure RECD is “Best practice in HA fitting for children”, monitor quality of RECD outcome and the consequences on target match in verification
• Verify fitting with simulated REAR in test box
– Minor deviations from target in certain frequencies are natural
– Monitor deviations from target match in high frequencies in relation to earmold quality and feedback issues
– SII Normative Values can help to assess own verification results in comparison to standards
– Average RECD is based on statics it is expected, that individual values deviate dependent on frequency
– Import RECD values to fitting software ease of recalculation for changes
Measure & verify regularly to monitor and adapt for consistent audibility!
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Thank you for listening!
Questions? Discussion?